Living in the present have been Mai's way through life. What she should do, why should she do it, how can she do it, living her life consciously with no doubts of the past or the future.
Fantasizing the future won't bring it any closer to reality, reminiscing the past won't come back. There are better things that can be doing with her time. By engaging in the present moment, it may not be always easy.
But Mai Mitsurugi care less for such things. Because the present her found the most precise moment to find her match.